Horn control system



May 19, 1942. J, WHTT 2,283,659

- nomg; CONTROL SYSTEM Filed May 25, 1939 I I 68 v I 74 E/vIqm/E FAN 80 r a2 :3

ACCELERA TOP PEDAL /06' /00 BRA KE RESPONS/VE s wrrcH W w azu ATToRN w Patented May 19, 1942 HORN CONTROL SYSTEM Joe White, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corpora- "tion of Delaware "Application May 26, 1939, Serial No. 275,898

' 1- Claim; (01. 177-7) This inventionrelates to a system of controls for automobile'horns and more particularly to the type of control which provides for the sounding of a warning signal of relatively low volume or relatively short duration suitable for city trafiic and a signal of longer duration and greater volume for country driving,

Automobiles are usually provided with a pair of matched horns differing. in frequency and having their frequencies so related that, when the horns are sounded simultaneously, a pleasing tone will be produced. It is an'object of the present invention to provide a system of control for a pair of horns which is normallyconditioned so that only one of the, horns can be sounded, and then only to give a tone of moderate volume, less than the volume which the horn is capable of producing. By means within the control of the driver or by automatic means responsive to engine speed or to engine acceleration or to the application of vehicle brakes, the system is conditioned so that both horns will be sounded with full volume whenever the horn button is pressed and these conditions prevail.

Further objects and advantages of the present invention will be apparent from, the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Figure 1 is a wiring diagram of asystem embodying the present invention il'l'WhlCh a man.- ually operated switch isemployedto control the energization of a control relay which changes the status of the system from city driving to country driving. v

Figure 2 shows diagrammatically.anengine exhaust manifold temperature responsive switch which maybe substituted for the manual switch of Figure 1.

Figure 3 shows diagrammatically an air switch which may be substituted for the manualswitch of Figure 1.

Figure 4 shows diagrammatically an' accelerator pedal operated switch which may be substituted for the manual switch of Figure 1.

Figure 5 is a diagram of a switch responsive to the application of vehicle brakes for performing the function of the manual switch shown in Figure 1.

Referring to Figure 1; horns 20 and 30 are a pair of matched horns having their frequencies so related that, when the horns are sounded together a pleasing tone will be produced. Horn 20 has an operating magnet coil 2| which produces movement of an armature connected with a diaphragm not shown. The movement of the armature intermittently opens a pair of normally closed contacts 22 and 23, the latter being grounded and the former being connected with the magnet coil 2|. For the purpose of reducing sparking at the contacts 22 and 23, a resistance 24 (two ohms for example) is connected in parallel with these contacts. Horn 20 is provided with two terminals, a main terminal 25 and a terminal 26 connected through a resistance 21 with the contact 22. Resistance 21 is less in amount than resistance 24, being about .1 ohm where resistance 24 is 2 ohms.

Horn 30 is provided with an operating magnet coil 3|, normally closed contacts 32 and 33, and a contact shunting resistance 34 of the same value as resistance 24. Horn 30 has a main terminal 35. y

- A storage battery 36 grounded at 31 is connected with the horn 20 through a relay-40 comprising a magnet winding 4|, an armature 42 and normally open contacts 43 and 44, the latter of which is connected by wire 45 with horn terminal 25. The relay winding 4| is connected to ground to a horn switch 50, comprising a button 5| connecting a contact 52 with a grounded contact 53. When the switch is closed, relay winding 4| is connected to ground thereby energizing relay 40 and effecting the engagement of contacts 43 and 44 thereby connecting the horn 20' with the battery through the following circuit: battery 35, armature 42, contact 43, contact 44, wire 45, terminal 25, horn magnet coil 2 ,horn contacts 22 and 23. Wire 45 is connected by wire 45a with one end .of magnet coil 6| of relay Bl]. The other end of coil 6| is connected by wire 68 with movable contact 12 of selector switch 10. In the B position, contact 12 opens the circuit of coil 6|. In the A position, contact 12 engages 1| which is grounded, thus making a connection between coil 6| and the battery 36. When contact 12 of switch 10 is in the A position and button 5| is closed, coil BI is connected with the battery 36, and armature 62 is attracted downwardly (Fig. 1) to separate contact 63 from contact 64 (connected with terminal 26 and resistance 21) and to move contact 65 into engagement with contact 66 (connected with terminal 35 of horn 30).

When the selector switch 10 is in the A position both horns, 20 and 30, sound with full volume. When the selector switch I0 is in the B position, horn 30 is silent and horn 20 sounds with reduced volume because the resistance 21 (then paralleling the magnet coil 2| of horn 20) operates to retard the decay of flux in coil 2| when the contacts 22 and 23 are separated by the movement of the diaphragm-operating armature (not shown). Since magnet coil 2| is connected at both ends with resistance 21, coil 2| will be partially saturated when contacts 22 and 23 are separated, due to the self induction of the coil 2|. That prevents complete decay of the magnetic flux in the coil 2| and thereby weakens the impulse applied to the diaphragm. In other words, when the contacts 22 and 23 are open, the resistance 21 forms a path for self induced current to flow in the coil 2| thereby reducing the variation in the current flowing in coil 2| and thereby reducing the effectiveness of the coil 2| to oscillate the diaphragm. Therefore the diaphragm operates with reduced amplitude and the horn operates to produce a relatively low volume of sound.

Instead of using the selector switch 70 to control the relay 60, a switch responsive to vehicle speed may be provided. Figure 2 shows a thermal switch 89 which is roughly responsive to vehicle speed. Switch 80 comprises a stationary contact 8| connected with wire 68 and normally out of engagement with a. movable contact 82 carried by a bimetallic blade 83 mounted in thermal relation to the engine exhaust pipe 84 and in electrical connection therewith whereby contact 82 is provided with a ground return to the battery 36. When the speed of the vehicle attains for example, a speed of 35 to 40 miles an hour, the temperature of the exhaust pipe will be sufiiciently elevated to cause the bimetallic blade 83 to bow upwardly to connect contact 82 with contact 8|, thereby grounding the relay coil 6| so that both horns will be sounded with full volume when the horn button is pressed.

A more accurate control of the system in accordance with engine speed is provided by the air switch 90, shown in Figure 3, which comprises a stationary contact 9| connected with wire 68 and normally out of engagement with an air vane contact 92 which is grounded. The engine cooling fan 94 creates a blast of air indicated by arrow 95 tending to move the air vane 92 against the action of the spring 93. When the vehicle speed is above 35 miles per hour for example, the vane 92 will engage the contact 9| for the purpose of grounding the relay coil 6|.

Relay coil 6| may be grounded also by an accelerator pedal operated switch I90 having a contact |0| connected with wire 68, and having a grounded contact I02 connected with contact |0| by a movable contact I03 held normally in circuit-open position by a spring Hi4. When accelerator pedal I95 is moved sufiiciently to produce rapid acceleration of the engine, it will engage a rod I06 to cause contact I03 to engage contacts HH and I02 for the purpose of grounding relay coil 6| The relay coil 6| may be grounded also by switch ||0 operating in response to the application of vehicle brakes. Switch ||0 comprises a fluid pressure chamber III in communication with a hydraulic brake operating system and having a flexible wall or diaphragm I I2 supporting a movable contact 3 capable of being moved into engagement with a stationary contact 4 connected with wire 68, and a grounded stationary contact ||5 Normally the contact 3 is held by a spring ||6 out of engagement with the stationary contact. When the vehicle brakes are applied the pressure in the chamber rises sufliciently to move the diaphragm ||2 downwardly to cause th contact 3 to engage the contacts 4 and H5, thereby completing a connection between ground and coil 6| of the current by-passing relay 60.

In the system shown in Figure 1 any of the switches shown in Figures 2, 3, 4 and 5 may be substituted for the selector switch 10 or may be connected in parallel with switch 10 in order to provide for the control of the short circuiting relay 60 either by manual means, by means responsive to vehicle speed, by means responsive to the accelerating of the engine, or by means responsive to the application of brakes.

From the foregoing description of the construction and mode of operation of my new system of controlling automobile horns it is apparent that I have a system which i normally conditioned for causing only one of a plurality of horns to give a relatively weak note during normal conditions of city driving and to cause all the horns to sound with full power When drivin in the country, or when it is desired to accelerate the engine, or whenever the vehicle brakes are applied, or may be controlled at will. The latter form of control may be preferred for commercial vehicles which are generally operated during the day for certain hours in a very congested district where the noise level is relatively high and the horn should be sounded at full volume at all times. Under those conditions the selector switch Ill should be closed. At times the vehicle is driven through districts which are relatively uncongested, such as residence districts or school or hospital zones, where the horns should not be sounded with full volume any more frequently than is necessary for safety. Under those condition of driving the selector switch 10 should be opened and the control of the system efiected by one or more of the switches shown in Figures 2 to 5.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form it is to be understood that other forms might be adopted, all coming Within the scope of the claim which follows.

What is claimed is as follows:

A horn control system comprising a current source, a horn having an operating magnet coil and a circuit breaker operated thereby, a switch for connecting the source with the magnet coil, a circuit for paralleling the magnet coil and including switch contacts and a resistance operable when the contacts are closed to retard the decay of flux of the magnet coil when the circuit breaker is open, and means for opening the contacts in the circuit paralleling the magnet coil.

JOE WHITE. 

